Spring MVC 4.2 增加 CORS 支持

跨站 HTTP 请求(Cross-site HTTP request)是指发起请求的资源所在域不同于该请求所指向资源所在的域的 HTTP 请求。比如说，域名A(http://domaina.example)的某 Web 应用程序中通过标签引入了域名B(http://domainb.foo)站点的某图片资源(http://domainb.foo/image.jpg)，域名A的那 Web 应用就会导致浏览器发起一个跨站 HTTP 请求。在当今的 Web 开发中，使用跨站 HTTP 请求加载各类资源（包括CSS、图片、JavaScript 脚本以及其它类资源），已经成为了一种普遍且流行的方式。

正如大家所知，出于安全考虑，浏览器会限制脚本中发起的跨站请求。比如，使用 XMLHttpRequest 对象发起 HTTP 请求就必须遵守同源策略（same-origin policy）。 具体而言，Web 应用程序能且只能使用 XMLHttpRequest 对象向其加载的源域名发起 HTTP 请求，而不能向任何其它域名发起请求。为了能开发出更强大、更丰富、更安全的Web应用程序，开发人员渴望着在不丢失安全的前提下，Web 应用技术能越来越强大、越来越丰富。比如，可以使用 XMLHttpRequest 发起跨站 HTTP 请求。（这段描述跨域不准确，跨域并非浏览器限制了发起跨站请求，而是跨站请求可以正常发起，但是返回结果被浏览器拦截了。最好的例子是crsf跨站攻击原理，请求是发送到了后端服务器无论是否跨域！注意：有些浏览器不允许从HTTPS的域跨域访问HTTP，比如Chrome和Firefox，这些浏览器在请求还未发出的时候就会拦截请求，这是一个特例。）

更多CORS介绍请看这里：

https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Access_control_CORS

在WEB项目中，如果我们想支持CORS，一般都要通过过滤器进行实现，可以定义一些基本的规则，但是不方便提供更细粒度的配置，如果你想参考过滤器实现，你可以阅读下面这篇文章：

http://my.oschina.net/huangyong/blog/521891

Spring MVC 从4.2版本开始增加了对CORS的支持

在Spring MVC 中增加CORS支持非常简单，可以配置全局的规则，也可以使用@CrossOrigin注解进行细粒度的配置。

使用@CrossOrigin注解

先通过源码看看该注解支持的属性：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Target</span>({ ElementType.METHOD, ElementType.TYPE })<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Retention</span>(RetentionPolicy.RUNTIME)<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Documented</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> @<span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">interface</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">CrossOrigin</span> {</span>    String[] DEFAULT_ORIGINS = { <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"*"</span> };    String[] DEFAULT_ALLOWED_HEADERS = { <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"*"</span> };    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> DEFAULT_ALLOW_CREDENTIALS = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span> DEFAULT_MAX_AGE = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1800</span>;    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * 同origins属性一样     */</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@AliasFor</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"origins"</span>)    String[] value() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">default</span> {};    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * 所有支持域的集合，例如"http://domain1.com"。     * <p>这些值都显示在请求头中的Access-Control-Allow-Origin     * "*"代表所有域的请求都支持     * <p>如果没有定义，所有请求的域都支持     *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @see</span> #value     */</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@AliasFor</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"value"</span>)    String[] origins() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">default</span> {};    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * 允许请求头重的header，默认都支持     */</span>    String[] allowedHeaders() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">default</span> {};    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * 响应头中允许访问的header，默认为空     */</span>    String[] exposedHeaders() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">default</span> {};    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * 请求支持的方法，例如"{RequestMethod.GET, RequestMethod.POST}"}。     * 默认支持RequestMapping中设置的方法     */</span>    RequestMethod[] methods() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">default</span> {};    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * 是否允许cookie随请求发送，使用时必须指定具体的域     */</span>    String allowCredentials() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">default</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>;    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * 预请求的结果的有效期，默认30分钟     */</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span> maxAge() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">default</span> -<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>;}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li></ul>

如果你对这些属性的含义不是很明白，建议阅读下面的文章了解更多:

http://fengchj.com/?p=1888

下面举例在方法和Controller上使用该注解。

在Controller上使用@CrossOrigin注解

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@CrossOrigin</span>(origins = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://domain2.com"</span>, maxAge = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3600</span>)<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@RestController</span><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@RequestMapping</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/account"</span>)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">AccountController</span> {</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@RequestMapping</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/{id}"</span>)    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Account <span class="hljs-title" style="box-sizing: border-box;">retrieve</span>(@PathVariable Long id) {        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// ...</span>    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@RequestMapping</span>(method = RequestMethod.DELETE, path = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/{id}"</span>)    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">remove</span>(@PathVariable Long id) {        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// ...</span>    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul>

这里指定当前的AccountController中所有的方法可以处理http://domain2.com域上的请求，

在方法上使用@CrossOrigin注解

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@CrossOrigin</span>(maxAge = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3600</span>)<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@RestController</span><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@RequestMapping</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/account"</span>)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">AccountController</span> {</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@CrossOrigin</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://domain2.com"</span>)    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@RequestMapping</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/{id}"</span>)    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Account <span class="hljs-title" style="box-sizing: border-box;">retrieve</span>(@PathVariable Long id) {        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// ...</span>    }    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@RequestMapping</span>(method = RequestMethod.DELETE, path = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/{id}"</span>)    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">remove</span>(@PathVariable Long id) {        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// ...</span>    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li></ul>

在这个例子中，AccountController类上也有@CrossOrigin注解，retrieve方法上也有注解，Spring会合并两个注解的属性一起使用。

CORS全局配置

除了细粒度基于注解的配置，你可能会想定义一些全局CORS的配置。这类似于使用过滤器，但可以在Spring MVC中声明，并结合细粒度@CrossOrigin配置。默认情况下所有的域名和GET、HEAD和POST方法都是允许的。

基于JAVA的配置

看下面例子：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Configuration</span><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@EnableWebMvc</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">WebConfig</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">WebMvcConfigurerAdapter</span> {</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">addCorsMappings</span>(CorsRegistry registry) {        registry.addMapping(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/**"</span>);    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li></ul>

您可以轻松地更改任何属性，以及配置适用于特定的路径模式的CORS：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Configuration</span><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@EnableWebMvc</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">WebConfig</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">WebMvcConfigurerAdapter</span> {</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">addCorsMappings</span>(CorsRegistry registry) {        registry.addMapping(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/api/**"</span>)            .allowedOrigins(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"http://domain2.com"</span>)            .allowedMethods(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"PUT"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"DELETE"</span>)            .allowedHeaders(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"header1"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"header2"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"header3"</span>)            .exposedHeaders(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"header1"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"header2"</span>)            .allowCredentials(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>).maxAge(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3600</span>);    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul>

如果你使用Spring Boot，你可以通过这种方式方便的进行配置。

基于XML的配置

<code class="language-xml hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mvc:cors</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mvc:mapping</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">path</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"/**"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mvc:cors</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

这个配置和上面JAVA方式的第一种作用一样。

同样，你可以做更复杂的配置：

<code class="language-xml hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mvc:cors</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mvc:mapping</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">path</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"/api/**"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">allowed-origins</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://domain1.com, http://domain2.com"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">allowed-methods</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"GET, PUT"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">allowed-headers</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"header1, header2, header3"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">exposed-headers</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"header1, header2"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">allow-credentials</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"false"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">max-age</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"123"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mvc:mapping</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">path</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"/resources/**"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">allowed-origins</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://domain1.com"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mvc:cors</span>></span></code>